JP2009270608A - Synthetic resin pipe and its connection structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin pipe easy to recycle while preventing the elongation and deflection of a pipe body. <P>SOLUTION: Between a plurality of layers 1, 2, a reinforcing wire rod 3 extending in the axial direction of the pipe body A' is embedded over the total axial length of the pipe body A'. The plurality of layers 1, 2 and the reinforcing wire rod 3 are each formed of an olefine resin. When the axial end of the pipe body A' is heated during connection, the plurality of layers 1, 2 are integrally welded to the reinforcing wire rod 3. Thus, the reinforcing wire rod 3 is preventive of come-off due to the movement in the pipe body A', thereby suppressing the axial elongation and arched deflection of the pipe body A' in high-temperature working environment. Since the plurality of layers 1, 2 and the reinforcing wire rod 3 use the same olefine resin, the whole pipe body A' can be scrapped as it is. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a synthetic resin pipe that is used as a conduit for hot water or other fluid or gas and is constructed by heat welding, and a pipe connection structure using the same.
Specifically, the present invention relates to a synthetic resin pipe and a pipe connection structure in which a pipe body is formed by laminating a plurality of layers and the pipe bodies are connected by heat welding.

Conventionally, as this kind of synthetic resin pipe, the inner layer, the intermediate layer and the outer layer of the pipe body are formed of the same polymer material (polypropylene random copolymer), and in the amorphous region of the polymer material of this intermediate layer, As a blocking material that suppresses the transfer of the additive from the inner layer to the outer layer, short cut glass fibers or endless fibers crushed in the mixing process, glass balls, or glass powder, or a filler made of a mixture of these materials, In addition, some include a binding additive that binds them (see, for example, Patent Document 1).
Further, as the pipe connection structure, the pipe end and the inner wall of the mounting part or the hole of the molded product are heated until the plastic flows with the tool, then the pipe and the mounting part are separated from the tool, and the pipe end is attached to the mounting part. Both parts are welded together by pushing into the hole.

JP 2001-355767 A (page 3-4, FIG. 1-2)

However, in such a conventional synthetic resin pipe, the pipe body is used because the inner layer, intermediate layer and outer layer of the pipe body are formed of thermoplastic resin and short-cut glass fibers or glass spheres. When the environment to be heated becomes hot due to hot water or the like, the inner layer, the intermediate layer and the outer layer are softened, and the entire pipe body extends in the axial direction, bends in a bow shape, and the pressure resistance performance is significantly reduced. There was a problem.
Furthermore, when the pipe body is disposed of, the filler made of glass fiber, glass sphere or glass powder or a mixture of these materials, and the binder additive that binds these must be separated from the intermediate layer and recycled. There was also a problem that it was difficult to do.
Further, in such a conventional pipe connection structure, when the pipe end is pushed into the hole of the mounting part, the molten resin flows out from the heating portion, and rises and cures in an annular shape from the inner peripheral surface of the pipe. There is also a problem that a predetermined flow rate may not be ensured by partially restricting the flow path.
Furthermore, the non-crystalline region of the polymer material in the intermediate layer contains a blocking material that suppresses the transfer of additives from the inner layer to the outer layer, resulting in poor impact resistance, thereby causing damage due to vibration or earthquake, for example. There is also a problem that it may be difficult to secure earthquake resistance.

The first invention of the present invention aims to facilitate recycling while preventing the pipe body from being stretched and bent.
In addition to the object of the first invention, the second invention aims to improve the pressure resistance of the pipe body.
The third invention is intended to prevent the molten resin from rising and curing on the inner peripheral surface of the pipe at the pipe connecting portion.
In addition to the object of the third invention, the fourth and fifth inventions aim to prevent the outflow hardening of the molten resin to the inner peripheral surface of the pipe reliably.

In order to achieve the above-mentioned object, the first invention of the present invention is such that a reinforcing wire extending in the axial direction of the pipe body is embedded between a plurality of layers over the entire axial length of the pipe body. The layer and the reinforcing wire are formed of an olefin resin.
The second invention is characterized in that a configuration in which the reinforcing wire is further spirally wound in the circumferential direction of the pipe body is added to the configuration of the first invention.
3rd invention is equipped with the synthetic resin pipe of 1st invention or 2nd invention, and the joint pipe fitted to the axial direction edge part of this synthetic resin pipe, The axial direction edge part of these synthetic resin pipes, A pipe connection structure in which a surface facing the joint pipe is melted by a heating means and welded by being brought into pressure contact with each other, wherein the synthetic resin pipe is formed from a pressure contact portion between the axial end of the synthetic resin pipe and the joint pipe. It is characterized by providing a flow regulating means for suppressing the flow of the molten resin toward the inside.
According to a fourth aspect of the invention, in the configuration of the third aspect of the invention, a sealing cover is provided as the flow restricting means, and a connecting portion between the axial end of the synthetic resin pipe and the joint pipe is provided from the inside of the synthetic resin pipe. It is characterized by the addition of a structure for mounting so as to cover.
According to a fifth aspect of the invention, in addition to the configuration of the third aspect of the invention, a configuration is provided in which a storage portion is formed as the flow restricting means at a pressure contact portion between the axial end portion of the synthetic resin pipe and the joint pipe. And

The first invention of the present invention embeds a reinforcing wire extending in the axial direction of the pipe body between the plurality of layers over the entire axial length of the pipe body, and the plurality of layers and the reinforcing wire are olefin-based. By forming the resin by heating the axial end of the pipe body at the time of connection, the multiple layers and the reinforcing wire are welded together, and the reinforcing wire does not move out of the pipe body, thereby Even when the environment of use of the pipe body becomes high, the elongation in the axial direction and the bow-like bending are suppressed, the impact resistance is remarkably improved, and the plurality of layers and the reinforcing wire are the same olefin resin. Therefore, the entire pipe body can be disposed of as it is.
Therefore, recycling can be facilitated while preventing the pipe body from being stretched and bent.
As a result, compared to the conventional pipe body made of thermoplastic resin, the linear strength of the pipe body is maintained, and after connecting the pipes, an unreasonable force is not applied to the connection part, Occurrence of accidents such as leaks can be completely prevented, and further, for example, it becomes difficult to break due to vibration or earthquake, so that sufficient earthquake resistance can be provided, and when discarding, the entire pipe can be reused without separation. Easy to use and recycle.

In the second invention, in addition to the effects of the first invention, the diameter expansion of the pipe body is suppressed by further winding the reinforcing wire in a spiral shape in the circumferential direction of the pipe body.
Therefore, the pressure resistance performance of the pipe body can be improved.

3rd invention is equipped with the synthetic resin pipe of 1st invention or 2nd invention, and the joint pipe fitted to the axial direction edge part of this synthetic resin pipe, The axial direction edge part of these synthetic resin pipes, A pipe connection structure in which a surface facing the joint pipe is melted by a heating means and welded by being brought into pressure contact with each other, wherein the synthetic resin pipe is formed from a pressure contact portion between the axial end of the synthetic resin pipe and the joint pipe. By providing the flow restricting means that suppresses the flow of the molten resin toward the inside, the molten resin that overflows from the facing surface with the pressure contact does not flow out to the inner peripheral side of the synthetic resin pipe A.
Accordingly, it is possible to prevent the molten resin from being raised and cured on the inner peripheral surface of the pipe at the pipe connection portion.
As a result, the inner peripheral surface of the pipe connecting portion is partially raised and does not restrict the flow path, so that a predetermined flow rate can be ensured.

In addition to the effects of the invention of the third invention, the fourth invention provides a sealing cover as a flow restricting means at the connection portion between the axial end of the synthetic resin pipe and the joint pipe, and the inner side of the synthetic resin pipe. As a result, the molten resin overflowing from the opposing surface with the pressure contact is guided along the outer peripheral surface of the synthetic resin pipe and hardened.
Therefore, the outflow hardening of the molten resin to the pipe inner peripheral surface can be reliably prevented.

In addition to the effects of the invention of the third invention, the fifth invention provides the pressure contact by forming a storage portion as a flow regulating means at the pressure contact portion between the axial end of the synthetic resin pipe and the joint pipe. Along with this, the molten resin overflowing from the facing surface flows into the reservoir and is cured.
Therefore, the outflow hardening of the molten resin to the pipe inner peripheral surface can be reliably prevented.

  In the embodiment of the synthetic resin pipe A of the present invention, as shown in FIGS. 1 to 2, a plurality of layers 1 and 2 made of a thermoplastic resin are laminated, and the axial direction is interposed between the plurality of layers 1 and 2. Reinforcing wire 3 extending in the axial direction of the layers 1 and 2 is embedded over the entire length in the axial direction, and the layers 1 and 2 and the reinforcing wire 3 are formed of an olefin resin such as polypropylene, for example. The pipe main body A ′ is formed by laminating, and the axial ends of the pipe main body A ′ are heated by a heating means such as a heater to be thermally welded to each other.

In the manufacturing method of the pipe main body A ′, at least an inner layer and an outer layer are sequentially extruded as the plurality of layers 1 and 2, and a reinforcing wire 3 to be described later is disposed and embedded between the inner layer 1 and the outer layer 2.
Although not shown as other examples, an intermediate layer is extruded between the inner layer 1 and the outer layer 2, and a reinforcing wire described later between the inner layer 1 and the intermediate layer and between the intermediate layer and the outer layer 2. It is also possible to bury them by arranging 3 respectively.

  Although not shown, an innermost layer made of a material matched to the fluid or gas passing through the pipe body A ′ is provided inside the inner layer 1 as necessary, or a protective material is formed outside the outer layer 2. It is also possible to provide an outermost layer.

  The reinforcing wire 3 is, for example, a thread such as a monofilament (monofilament) formed from the same polypropylene as the plurality of layers 1 and 2, a reinforcing fiber, and the like. If a plurality of thick monofilaments (stretched monofilaments) extending linearly in the axial direction of the main body A ′ are arranged at appropriate intervals in the circumferential direction, the pipe main body A ′ can be easily cut and reduced in weight while having excellent rigidity. To preferred.

As another example, a plurality of multifilaments knitted with thin monofilaments are arranged at appropriate intervals in the circumferential direction so as to extend linearly in the axial direction of the pipe body A ′, and the pipe body A It is also possible to form a hollow cylindrical uniform net by spirally braiding in the circumferential direction of ′, or knitting into a hollow cylindrical uniform net by knit knitting or the like.
Furthermore, instead of the drawn monofilament or multifilament, it is also possible to use a flat yarn (or tape yarn) made of tape-like yarn, in which case the thickness of the reinforcing wire 3 is reduced, There is an advantage that the thickness of the entire pipe body A ′ can be reduced.

And, the embodiment of the pipe connection structure using the synthetic resin pipe A of the present invention, as shown in FIG. Or as shown in FIGS. 3-5, the several synthetic resin pipe A is heat-welded through the coupling pipe B mentioned later.
The pipe connection structure includes a synthetic resin pipe A having the above-described structure, a joint pipe B that is fitted to the axial end A1 of the synthetic resin pipe A, an axial end A1 of the synthetic resin pipe A, and a joint pipe. Heating means (not shown) for melting the facing surfaces of B are provided, and the facing surfaces melted by the heating means are welded to each other.

  As a specific example, the inner diameter of the joint pipe B is formed to be equal to or smaller than the outer diameter of the axial end A1 of the synthetic resin pipe A, and the axial end A1 of the synthetic resin pipe A is formed. After heating the outer peripheral surface A2 and the inner peripheral surface B1 of the joint pipe B, the synthetic resin pipe A is pushed into the joint pipe B, whereby the joint inner peripheral surface B1 and the pipe outer peripheral surface A2 are pressed against each other and heated. Welding.

The joint pipe B is formed of the same thermoplastic resin as the layers 1 and 2 of the synthetic resin pipe A, specifically, an olefin resin such as polypropylene, and has openings corresponding to the number of synthetic resin pipes A to be connected. For example, it is integrally formed in a straight pipe or a T-shaped pipe.
In the illustrated example, a case is shown in which two openings of the joint pipe B are opened in a straight line, and two synthetic resin pipes A are respectively pushed into and connected to the openings.

Furthermore, if necessary, the inner peripheral surface B1 of the opening to which the axial end portion A1 of the synthetic resin pipe A is connected is provided with a step portion B2 where the axial front end surface A3 of the synthetic resin pipe A inserted therein abuts. It is preferable to integrally mold so as to project in a ring shape in the direction.
In this case, when the synthetic resin pipe A is pushed into the joint pipe B, the joint inner peripheral surface B1 and the pipe outer peripheral surface A2 are in pressure contact with each other, and at the same time, the step B2 in the joint pipe B and the synthetic resin pipe A The axial front end surface A3 is in pressure contact, and these pressure contact portions are welded to each other.

By the way, as shown in FIGS. 6 (a) and 6 (b), the synthetic resin pipe A is pushed into the opening of the joint pipe B as described above, and the opposing pipe outer peripheral surface A2 and the joint inner peripheral surface B1 are pressed, When the melted resin R overflows from these facing surfaces, the molten resin R going from the pressure contact portion to the inside of the synthetic resin pipe A rises from the inner peripheral surface A4 of the synthetic resin pipe A to the inside of the pipe and flows out as it is. It protrudes in a ring and hardens.
On the other hand, the molten resin R that goes from the pressure contact portion to the end surface B3 of the joint pipe B along the pipe outer peripheral surface A2 rises and flows out from the end surface B3 of the joint pipe B to the outside of the pipe, Protrusively hardens.
As a result, the annular resin R that has risen and hardened inward from the pipe inner peripheral surface A4 may partially squeeze the flow path to ensure a predetermined flow rate, and may be outside the pipe outer peripheral surface A2. The ring-shaped resin R which is raised and hardened may deteriorate the appearance.

Therefore, in order to solve such problems, in the present invention, the flow of the molten resin R from the axial end A1 of the synthetic resin pipe A, the joint pipe B, and the press-contact portion to the inside of the synthetic resin pipe A is suppressed. The flow regulating means C is provided.
As the flow regulating means C, as shown in FIGS. 3 (a) and 3 (b), the synthetic resin pipe A is connected to the connecting portion between the axial end A1 of the synthetic resin pipe A and the joint pipe B with a sealing cover C1. By attaching so as to cover from the inside of A, the molten resin R that overflows as the synthetic resin pipe A is pushed and pressed is guided and cured toward the end surface B3 of the joint pipe B along the outer peripheral surface A2. It is preferable to make it.

  As another example, as shown in FIGS. 4 (a), 4 (b) and 5 (a), 5 (b), a reservoir C2 is provided at the pressure contact portion between the axial end A1 of the synthetic resin pipe A and the joint pipe B. , C3, the molten resin R overflowing as the synthetic resin pipe A is pushed and pressed can be poured into the storage means C2 and C3 to be cured.

Further, as the olefin resin such as polypropylene constituting the plurality of layers 1 and 2 and the reinforcing wire 3, in the pipe connection structure, when the axial end faces of the synthetic resin pipe A are butted and welded together, the resin is soft. However, when a plurality of synthetic resin pipes A are thermally welded via the joint pipe B, the opening of the joint pipe B may be used. Since it is necessary to insert the synthetic resin pipe A, it is preferable to mold with a somewhat hard olefin resin.
Embodiments of the present invention will be described below with reference to the drawings.

  In the first embodiment, as shown in FIG. 1A, the above-described synthetic resin pipe A extends linearly in the axial direction along the outer peripheral surface 1a of the inner layer 1 after the inner layer 1 is extruded. A plurality of reinforcing wire rods 3 such as thick monofilaments (stretched monofilaments) are arranged at appropriate intervals in the circumferential direction, and the outer layer 2 is extruded on the outside thereof, thereby integrating the inner layer 1, the reinforcing wire rod 3 and the outer layer 2. The case where the pipe body A ′ is formed is shown.

Next, a connection example of such a synthetic resin pipe A will be described.
As shown in FIG. 1 (b), first, only the axial end portion or the axial end face of each pipe body A 'is heated by heating means (not shown) such as a heater, and then the pipe bodies A' are straightened. When the end faces are brought into contact with each other so as to be in line, the end portions in the axial direction of the inner layer 1, the outer layer 2 and the reinforcing wire 3 are melted and united, and the reinforcing wire 3 becomes the inner layer 1 and the outer layer 2 It is heat welded to.

  As a result, even if the pipe body A ′ is bent or deformed, the reinforcing wire 3 does not move between the inner layer 1 and the outer layer 2 and comes out. As a result, the environment in which the pipe body A ′ is used. Even in a high temperature atmosphere, the pipe body A 'is prevented from extending in the axial direction or bent in an arcuate shape, the linear strength of the pipe body A' is maintained, and the connection of each pipe body A ' No excessive force is applied to the part.

Further, since the inner layer 1, the outer layer 2 and the reinforcing wire 3 are made of the same olefin resin, the pipe body A 'can be discarded without being decomposed.
In the case of the illustrated example, an example is shown in which the molten resin R flowing out from the axial end faces of each pipe body A ′ rises to the inner side of the inner layer 1 and the outer side of the outer layer 2 and protrudes in an annular shape and hardens. However, as described above, it is preferable that at least the inner layer 1 is annularly raised and not hardened.

  In the second embodiment, as shown in FIG. 2, the above-described synthetic resin pipe A extrudes the inner layer 1, and then, along the outer peripheral surface 1a of the inner layer 1, a reinforcing wire 3 such as a multifilament or a flat yarn. Are arranged at appropriate intervals in the circumferential direction so as to extend linearly in the axial direction, and are braided in a spiral shape in the circumferential direction, and the outer layer 2 is extruded on the outside thereof, and the inner layer 1 is reinforced. The configuration in which the wire body 3 and the outer layer 2 are integrated to form the pipe body A ′ is different from the first embodiment shown in FIG. 1, and other configurations are the same as those in the first embodiment shown in FIG. is there.

Therefore, the second embodiment shown in FIG. 2 also has the same effect as the first embodiment described above, and in addition, the diameter of the inner layer 1 is suppressed by the reinforcing wire 3 wound spirally in the circumferential direction. Therefore, there is an advantage that the pressure resistance performance of the pipe body A ′ can be improved.
In addition, since the multifilament or flat yarn having a thickness smaller than that of the thick monofilament (stretched monofilament) is used as the reinforcing wire 3, the overall thickness of the synthetic resin pipe A can be made thinner and lighter than that of the first embodiment. There is also an advantage that can be achieved.

  As shown in FIGS. 3A and 3B, the third embodiment is either the synthetic resin pipe A of the first embodiment shown in FIG. 1 or the synthetic resin pipe A of the second embodiment shown in FIG. In one pipe connection structure, a sealing cover C1 as the flow restricting means C is attached from the inside of the synthetic resin pipe A to the portion where the pipe tip surface A3 and the step B2 in the joint B abut. Shows the case.

  The sealing cover C1 is formed of a synthetic resin or a metal having a melting temperature higher than that of an olefin resin such as polypropylene, which constitutes the synthetic resin pipe A and the joint B. It is preferable to project a clamping portion C1 ′ that is sandwiched between the axial front end surface A3 and the stepped portion B2 in the joint B.

Next, such a pipe connection structure will be described in detail in the order of processes.
First, as shown by a two-dot chain line in FIG. 3A, the outer peripheral surface A2 of the axial end A1 of the synthetic resin pipe A and the inner peripheral surface B1 of the joint pipe B facing the outer peripheral surface A1 are, for example, Each is heated by bringing heating means (not shown) such as a heater into contact therewith.

When the surface portions of the pipe outer peripheral surface A2 and the joint inner peripheral surface B1 reach a temperature at which they can be melted, the sealing cover C1 is sandwiched between the synthetic resin pipe A and the joint pipe B.
Thereafter, as shown in FIG. 3 (b), the heated pipe outer peripheral surface A2 is inserted along the heated joint inner peripheral surface B1, thereby bringing them into pressure contact with each other, and the pipe front end surface A3 being It abuts against the step B2 in the joint pipe B.

As a result, the molten resin R flowing out with the pressing of the synthetic resin pipe A and the pressure contact between the pipe outer peripheral surface A2 and the joint inner peripheral surface B1 has a gap between the pipe front end surface A3 and the joint means portion B2. Since it is sealed by the cover C1, it does not flow out from the pipe inner peripheral surface A4 side, all of which is guided along the pipe outer peripheral surface A2 toward the end surface B3 of the joint pipe B, and then flows out and annularly outwards. It rises and protrudes and hardens.
Therefore, Example 3 shown in FIGS. 3A and 3B can prevent the molten resin R from rising and curing on the pipe inner peripheral surface A4 at the pipe connection portion between the synthetic resin pipe A and the joint pipe B. Since the flow path is not restricted, a predetermined flow rate can be secured.

  As shown in FIGS. 4A and 4B, the fourth embodiment replaces the sealing cover C1 of the third embodiment shown in FIGS. 3A and 3B with a step B2 in the joint B. The storage portion C2 is recessed as the flow restricting means C so as to face the pipe inner peripheral surface A3, so that the molten resin R flowing out as the synthetic resin pipe A is pushed and pressed is supplied to the storage portion. The configuration for pouring into C2 and curing is different from the third embodiment shown in FIG. 3, and the other configuration is the same as the third embodiment shown in FIG.

  The storage part C2 is preferably formed in an annular shape over the entire circumference in the circumferential direction of the end face of the stepped part B2, and can be extended to the joint inner peripheral face B1 side in order to increase its capacity.

Therefore, the fourth embodiment shown in FIG. 4 can obtain the same operation and effect as the third embodiment described above. In addition, the fourth embodiment shown in FIG. In addition to being easy, there is an advantage that the number of parts can be reduced correspondingly and the cost can be reduced.
In addition, since part or most of the molten resin R flowing out as the synthetic resin pipe A is pushed in and pressed against the outer peripheral surface A2 of the pipe and the inner peripheral surface B1 of the joint flows into the storage portion C2, the outer peripheral surface A2 extends along the pipe. The amount of the molten resin R toward the end surface B3 of the joint pipe B is reduced, and as a result, the resin R that rises outward from the outer peripheral surface A2 of the pipe and hardens is greatly reduced and becomes inconspicuous. There are also advantages.

  As shown in FIGS. 5A and 5B, the fifth embodiment replaces the storage section C2 of the fourth embodiment shown in FIGS. 4A and 4B with a storage section C3 as the flow regulating means C. The configuration in which the molten resin R that flows out as the synthetic resin pipe A is pushed and pressed by being recessed so as to face the pipe front end surface A3 is poured into the storage portion C3 and cured is shown in FIG. Unlike the fourth embodiment shown in FIG. 4, the other configurations are the same as those of the fourth embodiment shown in FIG.

The storage portion C3 is inclined linearly or curvedly so that the pipe outer peripheral surface A2 side is most concave on the pipe front end surface A3 as shown in the example, while preventing the outflow to the pipe inner peripheral surface A4 side. It is preferable to increase the capacity.
As another example, it is also possible to form an annular storage portion C3 on the pipe front end surface A3 perpendicular to the axial direction of the synthetic resin pipe A.

  Therefore, the fifth embodiment shown in FIG. 5 also has the same effect as the fourth embodiment described above, and in addition, the pipe tip surface A3 is inclined so that the capacity of the storage portion C3 is increased as in the illustrated example. In this case, most of the molten resin R flowing out due to the pressing of the synthetic resin pipe A and the pressure contact between the pipe outer peripheral surface A2 and the joint inner peripheral surface B1 flows into the storage portion C3. Thus, there is an advantage that the amount of flowing out toward the end surface B3 of the joint pipe B is remarkably reduced, thereby eliminating the resin R which rises and hardens outward from the pipe outer peripheral surface A2, thereby improving the appearance.

  In Embodiments 3 to 5 of the pipe connection structure described above, the shaft of the synthetic resin pipe A inserted into the inner peripheral surface B1 of the opening to which the axial end A1 of the synthetic resin pipe A is connected. The step portion B2 with which the front end surface A3 abuts is formed so as to protrude, but is not limited thereto, and without the step portion B2, the axial end surfaces A3 of the two synthetic resin pipes A to be connected abut each other, You may make it weld the press-contact part of these front end surfaces A3, and the press-contact part of the said joint inner peripheral surface B1 and the said pipe outer peripheral surface A2.

One Example of the synthetic resin pipe of this invention is shown, (a) is a partially notched perspective view, (b) is a longitudinal cross-sectional view which shows the example of a connection. It is a partially cutaway perspective view showing another embodiment of the synthetic resin pipe of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS In the longitudinal cross-sectional view which shows one Example of the pipe connection structure of this invention, (a) has shown the state before a connection, (b) has shown the state after a connection. It is a longitudinal cross-sectional view which shows the other Example of the pipe connection structure of this invention, (a) has shown the state before a connection, (b) has shown the state after a connection. It is a longitudinal cross-sectional view which shows the other Example of the pipe connection structure of this invention, (a) has shown the state before a connection, (b) has shown the state after a connection. It is a longitudinal cross-sectional view which shows an example of a pipe connection structure, (a) has shown the state before a connection, (b) has shown the state after a connection.

Explanation of symbols

A Synthetic resin pipe A 'Pipe body 1 Inner layer 2 Outer layer 3 Reinforcing wire A1 Axial end A2 Outer peripheral surface (pipe outer peripheral surface) A3 Axial front end surface (pipe front end surface)
A4 Inner peripheral surface (pipe inner peripheral surface) B Joint pipe B1 Inner peripheral surface (joint inner peripheral surface) B2 Step (joint means)
B3 End face C Flow regulating means C1 Sealing cover C1 ′ Clamping part C2, C3 Storage part R Molten resin

Claims (5)

In a synthetic resin pipe in which a plurality of layers (1, 2) are laminated to form a pipe body (A '), and the pipe bodies (A') are connected to each other by heat welding,
A reinforcing wire (3) extending in the axial direction of the pipe body (A ′) is embedded between the plurality of layers (1, 2) over the entire axial length of the pipe body (A ′). A synthetic resin pipe, wherein the layers (1, 2) and the reinforcing wire (3) are formed of an olefin resin. The synthetic resin pipe according to claim 1, wherein the reinforcing wire (3) is further spirally wound in the circumferential direction of the pipe body (A '). A synthetic resin pipe (A) according to claim 1 or 2, and a joint pipe (B) fitted to an axial end (A1) of the synthetic resin pipe (A), the synthetic resin pipe (A) The pipe connection structure in which the opposed surfaces of the axial end (A1) and the joint pipe (B) are melted by heating means and are welded by being pressed against each other, and the axial direction of the synthetic resin pipe (A) It is characterized by providing a flow regulating means (C) for suppressing the flow of the molten resin (R) from the pressure contact portion between the end (A1) and the joint pipe (B) toward the inside of the synthetic resin pipe (A). Pipe connection structure. A sealing cover (C1) as the flow regulating means (C) is connected to the synthetic resin pipe (A1) and the joint pipe (B) at the connecting portion between the axial end (A1) and the joint pipe (B). The pipe connection structure according to claim 3, wherein the pipe connection structure is attached so as to cover from the inside of A). The storage part (C2, C3) is formed in the press-contact part of the axial direction edge part (A1) of the said synthetic resin pipe (A), and the said joint pipe (B) as the said flow control means (C). Pipe connection structure.

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